1. Field
One or more embodiments relate to a battery pack, and more particularly, to the structure of a battery pack.
2. Description of the Related Art
Recently, portable electric/electronic apparatuses such as cellular phones, notebook computers, or camcorders that are compact and light have been actively developed and produced. The portable electric/electronic apparatuses include a battery pack so as to be operated in a place where no power source is provided. The battery pack adopts a secondary battery capable of charging/discharging to be economical. A typical secondary battery may be a nickel-cadmium (Ni—Cd) battery, a nickel-metal hydride (Ni-MH) battery, a lithium (Li) battery, or a lithium ion (Li-ion) battery. In particular, the operation voltage of a Li-ion battery is about three times higher than that of a Ni—Cd battery and that of a Ni-MH battery. Also, a Li-ion battery is widely used as a power source for a portable electronic apparatus due to its high energy density. A secondary battery uses a Li-based oxide as a positive electrode active material and a carbon-based material as a negative electrode active material.
In general, secondary batteries are classified into a liquid electrolyte battery and a polymer electrolyte battery according to the type of an electrolyte. A battery using a liquid electrolyte is referred to as a Li-ion battery and a battery using a polymer electrolyte is referred to as a lithium polymer battery. In a secondary battery, a bare cell formed by sealing an electrode assembly and a case accommodating an electrolyte may be electrically connected to a protection circuit board. The bare cell charges and discharges electricity according to a chemical reaction. The protection circuit board controls charge/discharge of a bare cell to prevent overcharge and over-discharge so that the bare cell may be protected.